Polymer blends for use in making medical devices including catheters and balloons for dilatation catheters

ABSTRACT

A combination of polymeric components provides desired characteristics in forming medical instruments such as catheters and balloons for dilatation catheters. For example, a balloon material is formed from a blend of polymeric components, including a first crystalline polymeric component and a second softening polymeric component. Where the first two components are generally incompatible, the balloon material can also include a third compatibilizing agent to facilitate blending the first two polymeric components together. The first polymeric component can be a branched or straight chain polyamide having a molecular weight of at least about 5000, or a polyester prepared from aromatic dicarboxylic acids having 8 to 14 carbon atoms or aliphatic dicarboxylic acids having from 2 to 12 carbon atoms, and at least one glycol having the formula HO(CH 2 ) n OH, where n is an integer from 2 to 10, neopentyl glycol and cyclohexane dimethanol. The second polymeric component can be a polyolefin, an ethylene copolymer, a polyester block copolymer, or a polyamide block copolymer. The third polymeric component is preferably an ethylene copolymer having the formula E/X/Y where E is ethylene; X is an α, β-ethylenically unsaturated monomer derived from at least one of alkylacrylate, alkylmethacrylate, alkyl vinyl ether, carbon monoxide, sulfur dioxide, or mixtures thereof, where the alkyl groups contain 1-12 carbon atoms; and Y is an α, β-ethylenically unsaturated monomer containing a reactive group that forms a covalent bond with the first polymeric component. The polymeric blend can be irradiated to enhance the properties of the balloon material, including significantly increasing burst pressures.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates generally to a novel polymer blend thatcan be extruded, molded, or otherwise formed into articles ofmanufacture having certain desired characteristics. As examples, thepolymer blend of the invention can be processed to form medicalcatheters and more particularly concerns a balloon material for medicalballoon dilatation catheters made from blends of a first crystallinepolymer component, and a second softening polymer component. The balloonmaterial can also include a third compatibilizing polymer component.While the invention herein relates generally to polymer blends, it willbe discussed in terms of preferred end uses in medical devices such ascatheters and dilatation balloons. The subsequent discussion is notmeant to be limiting and is by way of examples and preferred uses.

[0003] 2. Description of Related Art

[0004] Catheters are well known for their usefulness in medicalapplications and in particular angioplasty procedures, for opening bloodvessels or other passageways in the body that may be blocked byobstructions or stenosis. Dilatation catheters are generally formed fromthin, flexible tubing having an inflatable balloon at or near a distaltip of the tubing that can be inflated with fluid pressure communicatedto the balloon through a lumen of the tubing. In a typical angioplastyprocedure, the balloon dilatation catheter is passed through thevasculature to the location of a stenosis in an artery, and the balloonis inflated to a predetermined size and shape to open the blockedartery.

[0005] It is desirable for balloons of balloon dilatation catheters tobe capable of inflating to a diameter of typically five to six timestheir uninflated diameter in order to be able to open an obstructedvessel. Other desirable properties of balloons for such balloondilatation catheters include strength, softness, flexibility and a thin,low profile which are important for achieving the performancecharacteristics of folding in an uninflated state, tracking, crossingand recrossing the area of the obstruction or stenosis in a vessel in anuninflated state. In addition, properties of burst strength, compliance,fatigue have been increasingly important in the continuing effort tocreate thinner, lower profile balloons for balloon dilatation catheterswith an ability to track, cross and recross increasingly narrow passagesin obstructed vessels. For purposes of this description, the ability tocross is defined as the ability of a balloon of a balloon dilatationcatheter to pass through a stenosis; the ability to recross is definedas the ability of the balloon of a balloon dilatation catheter to passthrough a stenosis more than once, or to pass through more than onestenosis; and the ability to track is defined as the ability of balloonof a balloon dilatation catheter to pass over a guidewire through thetortuous curves of the vasculature, in being guided to and from thelocation of a stenosis.

[0006] Polymeric materials that have been used for making medicaldevices, catheters, dilatation catheters, and balloons for balloondilatation catheters include polyethylene, polyolefins, polyvinylchloride, polyester, polyimide, polyethylene terephthalate (PET),polyamides, nylon, polyurethane, and the like. Balloons made of softpolyolefin or ethylene copolymers materials are typically foldable, andtrack and cross well, so that they can often be used more than once, andcan be used to cross multiple lesions. However, such balloons alsocommonly have high balloon compliance and low burst strengths, withratings of rated burst pressure of about 8-9 atm, and a mean burstpressure of about 10-15 atm. Balloons made from polyethyleneterephthalate (PET) are commonly stronger, with a higher rated burstpressure of about 14-18 atm, and a mean burst pressure of about 18-25atm. However, dilatation catheter balloons made of PET are generallystiff, not readily foldable and refoldable, and are susceptible toacquiring defects from mechanical handling. Dilatation catheter balloonsmade of PET are also susceptible to pin-hole failures that can causejet-streaming of pressurized fluid within an artery, and can lead to adissection of the artery. As a result, to reduce the likelihood ofpin-hole failures, clinical applications of balloons made of this typeof material have generally been limited to thicker balloons that arecommonly limited to a single use, and for crossing a single lesion.

[0007] Examples of prior art compositions that may be suitable informing medical devices such as catheters, dilatation catheters, andballoon materials for use in angioplasty procedures include U.S. Pat.No. 4,753,980 (Deyrup); U.S. Pat. No. 4,172,859 (Epstein); U.S. Pat. No.5,091,478 (Saltman); U.S. Pat. No. 5,306,246 (Sahatjian et al.); U.S.Pat. No. 4,254,774 (Boretos); U.S. Pat. No. 4,964,409 (Tremulis); andU.S. Pat. No. 5,017,325 (Jackowski et al.), all of which areincorporated herein by reference. These references are presented by wayof example only and are not intended to be exhaustive of the prior art.

[0008] It would be desirable to provide a polymeric blend for balloonsfor balloon dilatation catheters with a combination of the best featuresof the softer balloon materials and the stronger balloon materials,including good flexibility, folding, track, cross and recross, with athin, low profile, high resistance to fatigue, low compliance, and highburst strength, with a lower susceptibility to defects throughmechanical handling, and a lower susceptibility to pin-hole defects,compared with balloons made from PET. The present invention meets theseneeds.

SUMMARY OF THE INVENTION

[0009] Briefly, and in general terms, the present invention provides fora catheter and/or balloon material formed from a blend of polymericcomponents that has surprisingly high rated and mean burst pressurecharacteristics, low compliance and excellent fatigue resistance, alongwith excellent folding and performance characteristics, such as track,cross and recross, allowing for construction of dilatation catheterballoons with the ability to cross multiple lesions.

[0010] The invention accordingly provides for a catheter and/or balloonmaterial formed from a blend composition of a first crystallinepolymeric component and a second softening polymeric component. When thefirst and second polymeric components are essentially incompatible inthat they are immiscible, and do not normally bond together well, athird compatibilizing agent that helps to strengthen the interfacebetween the two incompatible materials and to facilitate blending of thefirst two polymeric components can be added to the balloon material.

[0011] The first polymeric component generally consists of about 10-95%by weight of the total blend composition, and in one preferredembodiment can be a polyester prepared from the group of dicarboxylicacids selected from aromatic dicarboxylic acids having from 8 to 14carbon atoms and aliphatic dicarboxylic acids having from 2 to 12 carbonatoms, and at least one glycol selected from the group consisting ofglycols having the formula HO(CH₂)_(n)OH, where n is an integer from 2to 10, neopentyl glycol and cyclohexane dimethanol. In an alternativeembodiment, the first polymeric component can be a branched or straightchain polyamide having a molecular weight of at least about 5000. Thesecond polymeric component generally consists of about 5-90% by weightof the total blend composition, is selected to have a Shore hardnessless than 75 D, and preferably less than 55 D, and is selected from thegroup consisting of ethylene copolymers, polyolef ins having a densityless than 0.93, polyester block copolymers and polyamide blockcopolymers. The third polymeric component generally consists of anamount of a compatibilizing ethylene copolymer that is less than about2.5% by weight of the total balloon material blend, and preferably about0.25% to about 2.5% by weight of the total balloon material blend, andhas the formula E/X/Y where E is ethylene; X is an α, β-ethylenicallyunsaturated monomer derived from at least one of vinyl acetate,alkylacrylate, alkylmethacrylate, alkyl vinyl ether, carbon dioxide,sulfur dioxide, or mixtures thereof, where the alkyl groups contain 1-12carbon atoms; and Y is an α, β-ethylenically unsaturated monomercontaining a reactive group that will form a covalent bond with thefirst polymeric component. Alternatively, suitable catheter and/orballoon materials can be prepared that contain up to about 20% by weightof the third polymeric component.

[0012] The first polymeric component preferably comprises about 60-77%of the total blend composition, and in a preferred embodiment isselected from the group consisting of polyethylene-terephthalate,polybutylene-terephthalate, glycol modified polyethylene-terephthalate,1,4-cyclohexylene dimethylene terephthalate/isophthalate copolymer,linear homopolymer esters derived from aromatic dicarboxylic acids andglycols of the general formula HO(CH₂)_(n)OH where n is an integer from2 to 10. In a preferred aspect of the invention, the second polymericcomponent is a softening ethylene copolymer comprising about 23-40% byweight of the total blend composition, and contains ethylene and atleast one other monomer selected from the group consisting of α,β-ethylenically unsaturated monomers, carbon monoxide, and sulfurdioxide. In one particularly preferred embodiment, the softeningethylene copolymer has the formula E′X′ or E′X′Y′, where E′ is ethylene,and is about 60-85% by weight of the ethylene copolymer, and where X′ isabout 15-40% by weight of the ethylene copolymer, and X′ is selectedfrom the group consisting of methylacrylate, ethylacrylate,propylacrylate, butylacrylate, and mixtures thereof, and Y′, if present,is an α, β-ethylenically unsaturated monocarboxylic acid, di-acid oranhydride comprising about 0.5-15% by weight of the ethylene copolymer.Examples of Y′ include but are not limited to acrylic acid, methacrylicacid, fumaric acid and maleic anhydride. Where one of the X′ or Y′monomers is an acid containing moiety, the polymer can also be at leastpartially neutralized with an ion selected from the group of sodium,potassium, zinc, lithium, calcium, and ammonium. In a preferredembodiment, in the third polymeric component, X is selected from thegroup consisting of vinyl acetate, methylacrylate, butylacrylate, andmethyl vinyl ether, Y is an α, β-ethylenically unsaturated monomercontaining a reactive group selected from the group consisting ofepoxide, maleic anhydride, isocyanate, or oxazoline. In one preferredembodiment, Y is selected from the group consisting of glycidylacrylate, glycidyl methacrylate, and epoxide containing copolymerizablemonomers. In one currently particularly preferred embodiment, in thethird polymeric component, E is ethylene, and is 67% by weight of thecompatibilizing ethylene copolymer; X is selected from the group ofmethylacrylate, ethylacrylate, and butylacrylate, and is about 15-30% byweight of the compatibilizing agent; and Y is selected from the groupconsisting of glycidyl acrylate and glycidyl methacrylate, and is about8% by weight of the compatibilizing agent.

[0013] These and other aspects and advantages of the invention willbecome apparent from the following detailed description of the preferredembodiments.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The present invention relates to a polymer blend having certaincharacteristics generally desirable in medical devices. The polymerblend described herein is particularly suitable for use in formingmedical products such as catheters, dilatation catheters, and preferablyballoon material for use with catheters.

[0015] While dilatation catheter balloons made of soft polyolefin orethylene copolymer materials have generally good performancecharacteristics, such balloons also commonly have high ballooncompliance and low burst strengths. Dilatation catheter balloons madefrom strong polymeric materials such as polyethylene terephthalate (PET)have higher rated and mean burst pressures, but are generally stiff, notreadily foldable and refoldable, and are susceptible to acquiringdefects from mechanical handling, and are susceptible to pin-holefailures that can seriously injure the vasculature of a patient. Whilethe embodiments discussed herein refer generally to balloon materials,it is to be understood that the invention relates to catheters as wellhaving the polymer blends as described.

[0016] The invention accordingly is embodied in a balloon material forballoon dilatation catheters with a combination of the best features ofthe softer balloon materials and the stronger balloon materials,including high burst strength, low compliance, good flexibility, highresistance to fatigue, the ability to fold, track, cross and recrosswell, and with a lower susceptibility to defects through mechanicalhandling, and a lower susceptibility to pin-hole defects, compared withballoons made from PET. The balloon material is formed from a blend ofthree polymeric components, comprising a strong polymeric component, asoftening polymeric component that are generally incompatible, and acompatibilizing polymeric component that forms a covalent bond with oneof the first two polymeric components, and prevents the first twopolymeric components from separating when formed as a balloon for aballoon dilatation catheter.

[0017] The first polymeric component, component A, is preferably arelatively strong crystalline polymer, preferably comprising about60-77% of the total blend composition, although blend compositions ofthe invention comprising as little as 10% or as much as 95% of the totalblend composition may also be suitable. In one currently preferredembodiment, component A comprises PET, but can also comprise otherpolyesters, or polyamides. Other polyesters which can be used ascomponent A include polyesters prepared from an aromatic dicarboxylicacid having from 8 to 14 carbon atoms and at least one glycol, includingthose having the formula HO(CH₂)_(n)OH where n is an integer of 2 to 10,neopentyl glycol and cyclohexane dimethanol. The dicarboxylic acid mayalso be an aliphatic dicarboxylic acid having from 2 to 12 carbon atoms.Examples of other suitable polyesters include, but are not limited to,polybutylene-terephthalate (PBT), glycol modified PET (PETG),1,4-cyclohexylene dimethylene terephthalate/isophthalate copolymer andother linear homopolymer esters derived from aromatic dicarboxylic acidsand glycols of the general formula HO(CH₂)_(n)OH where n is an integerfrom 2 to 10. Such aromatic dicarboxylic acids include isophthalic,bibenzoic, naphthalene-dicarboxylic including the 1,5-; 2,6-; and2,7-naphthalenedicarboxylic acids; 4,4′-diphenylenedicarboxylic acid;bis(p-carboxyphenyl) methane; ethylene-bis-p-benzoic acid;1,4-tetramethylene bis(p-oxybenzoic) acid; ethylene bis(p-oxybenzoic)acid; 1,3-trimethylene bis(p-oxybenzoic) acid; and 1,4-tetramethylenebis(p-oxybenzoic) acid. Preferred glycols include ethylene glycol;1,3-trimethylene glycol; 1,4-tetramethylene glycol; 1,6-hexamethyleneglycol; 1,8-octamethylene glycol; 1,10-decamethylene glycol;2,2-dimethyl-1,3-propane diol; 1,3-propylene glycol; 1,4-butyleneglycol; neopentyl glycol and cyclohexane dimethanol.

[0018] Polyamides which are suitable for use as component A includebranched or straight chain polyamides having a molecular weight of atleast 5000, and commonly referred to as nylons; produced by condensationof equimolar amounts of a saturated dicarboxylic acid containing from 4to 12 carbon atoms with a diamine, in which the diamine contains from 4to 12 carbon atoms. Examples of suitable polyamides include, but are notlimited to, nylons such as polyhexamethylene adipamide (nylon 6,6),polyhexamethylene azelaamide (nylon 6,9), polyhexamethylene sebacamide(nylon 6,10), polyhexamethylene dodecanoamide (nylon 6,12), nylon 6,nylon 11, and nylon 12. Other polyamides that can be suitable includepolyamide block copolymers such as those sold under the trade name“PEBAX” by Atochem; polyamides including polyamides produced by the ringopening of lactams such as polycaprolactam, polylauric lactam,poly-11-amino-undecanoic acid, and bis(paraaminocyclohexyl) methanedodecanoamide; and polyamides prepared by the copolymerization orterpolymerization of such polymers. The polyamides preferably have amelting point in excess of 200° C.

[0019] The second polymeric component, component B, is selected to be asoftening polymer, preferably comprising about 23-40% by weight of thetotal balloon material composition, although blends of the balloonmaterial comprising as little as 5% of component B and as much as 90% ofthe total blend composition may also be suitable. In a currentlypreferred embodiment, component B comprises a softening polymercomponent having a Shore hardness less than 75 D, and preferably lessthan 55 D, and is preferably an elastomeric ethylene copolymer 10selected from the group of ethylene copolymers comprising ethylene andat least one other monomer selected from the group of α, β-ethylenicallyunsaturated monomers, carbon monoxide (CO), sulfur dioxide (SO₂).Component B is most preferably an elastomeric ethylene copolymer havingthe formula E′X′ or E′X∝Y′, where E′ is ethylene and comprises about60-85% by weight of the ethylene copolymer, X′ is acrylate ormethacrylate monomer, comprising about 15-40% of the ethylene copolymer,and Y′, if present, is an α, βethylenically unsaturated monocarboxylicacid, di-acid or anhydride comprising about 0.5-15% by weight of theethylene copolymer. Examples of Y′ include but are not limited toacrylic acid, methacrylic acid, fumaric acid and maleic anhydride. Otherpolymeric materials that may be suitable for use as component B include,but are not limited to, polyester block copolymers (containing one ormore of the following glycols) comprising hard segments ofpolyethylene-terephthalate or polybutylene-terephthalate, and softsegments of polyether such as polyethylene glycol, polypropylene glycolor polytetramethylene glycol ethers, such as those available under thetradename “HYTREL” from DuPont. Long chain glycols which can be used toprepare such copolyester polymers include poly(alkylene oxide) glycolsin which the alkylene group has 2-10 carbon atoms, such as poly(ethyleneoxide) glycol, poly(1,2- and 1,3-propylene oxide) glycol,poly(tetramethylene oxide) glycol, poly(pentamethylene oxide) glycol,poly(hexamethylene oxide) glycol, poly(heptamethylene oxide) glycol,poly(octamethylene oxide) glycol, poly(nonamethylene oxide) glycol, andpoly(1,2-butylene oxide) glycol, random or block copolymers of ethyleneoxide and 1,2-propylene oxide, and poly-formals prepared by reactingformaldehyde with glycols, or mixtures of glycols, such as a mixture oftetramethylene and pentamethylene glycols, and glycols formed fromdicarboxymethyl acids of poly(alkylene oxides); polyetherimide esterssuch as those produced under the tradename “LOMOD” by General Electric;polyesters available from Dutch State Mines under the trade name“ARNITEL”; polyamide block copolymers, such as those available fromAtochem under the tradename “PEBAX”; and polyolefins having a densityless than 0.93, including elastomeric ethylene-propylene copolymers,linear low density polyethylene (LLDPE), and linear low densitypolyethylene (LLDPE) including maleic anhydride.

[0020] The most preferred ethylene copolymers which can be used ascomponent B include, but are not limited to,ethylene/methylacrylate/sulfur dioxide (E/MA/SO₂),ethylene/butylacrylate/carbon monoxide (E/BA/CO),ethylene/methylacrylate (E/MA), ethylene ethylacrylate (E/EA),ethylene/butylacrylate (E/BA), ethylene/vinylacetate (E/VA),ethylene/methacrylic acid (E/MAA or E/AA),ethylene/butylacrylate/methacrylic acid (E/BA/MAA or E/BA/AA),ethylene/methylacrylate/methacrylic acid (E/MA/MAA or E/MA/AA),ethylene/butylacrylate/maleic anhydride (E/BA/Manh) orethylene/methylacrylate/maleic anhydride (E/MA/Manh). Where one of theα, β-ethylenically unsaturated monomers is an acid containing moiety,the polymer can be partially neutralized with an ion such as Na+, K+,Zn++, Li+, Ca++, NH4+, or the like. The acid groups in the unsaturatedmono-carboxylic acid are neutralized from 0-80% by at least one metalion selected from the group consisting of sodium, zinc, magnesium,calcium, potassium, and lithium. The third polymeric component,component C, is preferably an ethylene copolymer that functions as acompatibilizing agent or surfactant, in that it forms a covalent bondwith the first polymeric component, and blends compatibly with thesecond polymeric component. Component C preferably comprises from zeroto about 2.5% of the total blend composition, having the formula E/X/Y,where E is about 67%, X is about 25%, and Y is about 8% by weight of thecompatibilizing ethylene copolymer, and

[0021] E is ethylene,

[0022] X is an α, β-ethylenically unsaturated monomer derived from atleast one of alkylacrylate, alkylmethacrylate, alkyl vinyl ether, carbondioxide, sulfur dioxide, or mixtures thereof, where the alkyl groupscontain 1-12 carbon atoms, such as vinyl acetate, methylacrylate,butylacrylate, and methyl vinyl ether. X can, for example be a moietyderived from at least one of alkyl acrylate, alkyl methacrylate, alkylvinyl ether, carbon monoxide, sulfur dioxide, or mixtures thereof. Morespecifically, X can, for example, consist of 0-35 weight percent of amoiety derived from at least one alkyl acrylate, alkyl methacrylate, ormixtures thereof where the alkyl groups contain 1-8 carbon atoms.

[0023] Y is an α, β-ethylenically unsaturated monomer containing areactive group, such as epoxide, maleic anhydride, isocyanate, oroxazoline, for example, that forms a covalent bond with said firstpolymeric component. In one preferred embodiment, Y is selected from thegroup consisting of glycidyl methacrylate and glycidyl acrylate, maleicanhydride, and isocyanato-ethylmethacrylate.

[0024] In one currently preferred embodiment the first polymericcomponent of the balloon material blend comprises about 70-77% by weightPET; about 23-30% by weight of component B, which comprises an ethylenecopolymer having the formula E′X∝, where E′ is ethylene, and is about75% by weight of the ethylene copolymer, and X′ is selected from thegroup of ethylene methylacrylate, ethylene ethylacrylate, ethylenepropylacrylate, and ethylene butylacrylate, and is about 25% by weightof the ethylene copolymer; and from about 0.25% to about 2.5% by weightof component C, which is an ethylene copolymer having the formula EXY,where E is ethylene, and is 67% by weight of component C; X is selectedfrom the group of ethylene acrylate and ethylene methylacrylate, and isabout 25% by weight of component C; and Y is selected from the groupconsisting of glycidyl methacrylate, glycidyl ethylacrylate, andglycidyl butylacrylate, and is about 8% by weight of component C. Thesecond polymeric component, component B, is most preferably anelastomeric ethylene copolymer selected from the group consisting ofethylene/methylacrylate, ethylene/ethylacrylate, ethylene/butylacrylate,ethylene/methylacrylate/maleic anhydride, ethylene/ethylacrylate/maleicanhydride, and ethylene/butylacrylate/maleic anhydride; and the thirdpolymeric component, component C, is most preferably an ethyleneacrylate ester where X is selected from methyl acrylate, ethyl acrylateand butyl acrylate, and Y is selected from the group consisting ofglycidyl acrylate and glycidyl methacrylate.

[0025] In addition, in a preferred aspect of the invention, the balloonmaterial of the invention can advantageously be irradiated usingionizing radiation from an electron beam, gamma rays, ultraviolet light,or a molecular beam, to significantly alter the properties of theballoon material to provide improved balloon performance such as higherburst pressures. For example, where the balloon material was subjectedto an electron beam of about 10-100 MRads and energies of 100-200,000keV, higher burst strengths and higher fatigue strengths were obtainedfrom the balloon material.

[0026] The balloon materials of the invention provide dilatationcatheter balloons with the ability to cross multiple lesions, goodtrack, cross, and folding, low compliance with rated burst pressures ofabout 10-15 atm, and mean burst pressures of about 14-20 atm. Balloonsmade from the balloon material of the invention also typically have alower susceptibility to defects through mechanical handling than PET.When exposed to ionizing radiation to toughen the balloon material, thefatigue and burst strengths are substantially increased, to give ratedburst pressures of 12-14 atm or greater, mean burst pressures of 19-20atm, and a compliance of about 0.02-0.03 (mm/atm).

EXAMPLE 1

[0027] A polymer blend containing 80 weight % PET Traytuf 9506Cmanufactured by Shell, and 20 weight % ethylene ethylacrylate (EEA) DPDA6182 manufactured by Union Carbide, was produced by compounding in atwin screw extruder set for low shear conditions. The PET and EEA weremixed in a weight ratio of 80/20. The PET/EEA mixture was loaded intothe hopper of the compounder. The barrel temperatures were set to 410°F. in zone 1, 490° F. in zones 2 and 3, and 480° in zone four and at thehead of the barrel, the screw speed was maintained at 150 RPM, and thematerial was pelletized. Balloon tubing having an inner diameter of0.018 inches and an outer diameter of 0.036 inches was extruded usingthe 80/20 PET/EEA blend. The 80/20 PET/EEA blended material was dried.The barrel and die temperatures of the extruder were set, with zone 1 at390° F., zone 2 at 480° F., zone 3 at 500° F. and the clamp, die 1 anddie 2 at 510° F. The melt temperature of the blend was 574° F.Examination with a scanning electron microscope of a portion of theblend before extrusion into balloon tubing showed that the EEA formedspherical particles with a diameter greater than one micron, with poorinterfacial adhesion within the PET matrix. A section of the extrudedballoon tubing was also examined with a scanning electron microscope,showing that the EEA formed tubules in the extruded balloon tubing thatpulled out of the PET matrix.

EXAMPLE 2

[0028] The blend of PET and EEA from Example 1 was compounded andblended with 2% of the total blend composition by weight of a thirdcomponent, E/EA/GMA, as a compatibilizer, available as Lotader AX8660from AtoChem. Examination with a scanning electron microscope of aportion of the blend before extrusion into balloon tubing showed thatthe EEA formed a much better dispersion with better interfacial adhesionwithin the PET matrix, with little or no particle pull-out from the PETmatrix. A section of the extruded balloon tubing made from the blend wasalso examined with a scanning electron microscope, showing that the EEAformed no tubules in the extruded balloon tubing, and that the dispersedparticles of EEA were well adhered to the PET matrix. The material had aburst pressure of about 50 psi higher than in Example 1.

EXAMPLES 3-10

[0029] Balloon material blends were also formed using PET available asTraytuf 9506C from Shell, with a tensile strength of 7000 psi(non-oriented), and 10000-12000 (oriented), an elongation of 400-500%(after yield), a flexural modulus of 500,000-600,000 psi, and a meltingpoint of 257° C. EEA available as DPDA 6182 from Union Carbide was usedin Examples 3-5 and 8-10, with a tensile strength of 2300 psi,elongation of 670%, a flexural modulus of 6400 psi, a melt index of 1.5,a durometer of 91 A, a melting point of 85 C, a density of 0.93 and aVicat Softening index of 64. EMAC available as TC130 from Exxon was usedin Examples 6 and 7, with a tensile strength of 1200 psi, an elongationof 1600%, a flexural modulus of 3300 psi, a melt index of 20, aDurometer of 85 A, a melting point of 79 C, a density of 0.94 and aVicat Softening index of 50. Lotryl 24MA005 (EMA) from AtoChem was usedas the softening component in Example 10, with a tensile strength of2910 psi, elongation of 700%, a melt index of 0.5, a Durometer of 84 A,a melting point of 70 C., and a Vicat Softening index of 43. LotaderAX8660 (67% E, 25% EA, 8% GMA) from AtoChem was used as thecompatibilizing agent in Examples 4-10, with a tensile strength of 509psi, an elongation of 700%, a melt index of 6.0, a Durometer of 60 A, amelting point of 63 C., and a Vicat Softening index of 34.

[0030] The blend compositions of Examples 3-10 are listed in Table Ibelow, and were compounded under the compounding conditions noted inTable II and were extruded under the tubing extrusion conditions notedin Table III. TABLE I Example PET % EEA % EMAC % Lotryl % Lotader % 3 6040 — — — 4 78.4 19.6 — — 2 5 76 19 — — 5 6 78.4 — 19.6 — 2 7 76 — 19 — 58 68.8 29.5 — — 1.7 9 59.1 39.4 — — 1.5 10 70 — — 28 2

[0031] TABLE II Example 3 4 5 6 7 8 9 10 T1 ° F. 410 410 410 400 400 400400 275 T2 ° F. 490 480 480 480 480 450 450 480 T3 ° F. 490 480 480 490490 485 485 535 T4 ° F. 480 500 500 515 515 500 500 555 Thead ° F. 480500 500 515 515 500 500 555 RPM 150 150 150 150 150 150 150 150 Dry ° F.300 200 200 200 200 200 200 200

[0032] TABLE III Example 3 4 5 6 8 10 T1 ° F. 390 400 400 370 400 405 T2° F. 480 480 480 430 480 485 T3 ° F. 500 510 510 480 500 490 Tclamp 510510 510 480 500 490 ° F. Tdie1 510 510 510 480 500 490 ° F. Tdie2 510510 510 480 500 500 ° F. I. D. .018 .020 .020 .020 .020 .020 inches O.D. .036 .040 .040 .040 .040 .040 inches Dry ° F. 150 150 150 150 150 150

EXAMPLE 11

[0033] In Example 11, a blend composition was compounded according tothe method of Example 1. Tubing was extruded with an inner diameter of0.18 inches, an outer diameter of 0.036 inches, and a double wallthickness (DWT) of 0.00135 inches. The balloon formed from the tubingwas subjected to 25 Mrads of radiation, and had a mean burst pressure of250 psi.

EXAMPLES 12-13

[0034] In Examples 12 and 13, a blend composition was compoundedaccording to the method of Example 2. In Example 12, tubing was extrudedwith an inner diameter of 0.020 inches and an outer diameter of 0.040inches. Balloons were formed with an outer diameter of 0.119 in., a DWTof 0.0015 in., and were subjected to 40 Mrads of radiation anddemonstrated higher burst pressures. For example, the balloon formedfrom the tubing had a mean burst pressure of 285 psi (19.4 atm). Tubingnot subjected to irradiation was formed into a balloon with an outerdiameter of 0.1195 in., a DWT of 0.00145 in., and a mean burst pressureof 252 psi (17.1 atm).

EXAMPLES 14-15

[0035] In Examples 14 and 15, a polymer blend containing 90 weight % PETTraytuf 9506C manufactured by Shell, and 10 weight percent of anionomeric resin of ethylene and methacrylic acid, available under thetradename “SURLYN,” manufactured by DuPont, were blended. The materialswere separately dried. Balloon tubing having an inner diameter of 0.021inches and an outer diameter of 0.0325 inches was extruded using this90/10 blend. The barrel and die temperatures of the extruder were setwith Zone 1 at 460° F., Zone 2 at 485° F., Zone 3 at 500° F., die 1 at520° F., die 2 at 520° F.

[0036] In Example 14, a balloon was formed and material had a mean burstpressure of 207 psi (14.1 atm).

[0037] In Example 15, tubing was formed as in Example 13. The tubing wassubjected to 20 Mrads of radiation. The balloons formed had a mean burstpressure of 255 psi (17.3 atm).

[0038] It will be apparent from the foregoing that while particularforms of the invention have been illustrated and described, variousmodifications can be made without departing from the spirit and scope ofthe invention. Accordingly, it is not intended that the invention belimited, except as by the appended claims.

What is claimed is:
 1. A polymeric blend, comprising: about 10-95% byweight of the total blend composition of a first polymeric componentselected from the group consisting of polyesters and polyamides, saidpolyesters being prepared from the group of dicarboxylic acids selectedfrom aromatic dicarboxylic acids having from 8 to 14 carbon atoms andaliphatic dicarboxylic acids having from 2 to 12 carbon atoms, and atleast one glycol selected from the group consisting of glycols havingthe formula HO(CH₂)_(n)OH, where n is an integer from 2 to 10, neopentylglycol and cyclohexane dimethanol, and said polyamides being branched orstraight chain polyamides having a molecular weight of at least 5000;about 5-90% by weight of the total blend composition of a second polymercomponent having a Shore hardness less than 75 D, selected from thegroup consisting of polyolef ins having a density less than 0.93,ethylene copolymers, polyester block copolymers, and polyamide blockcopolymers; and less than about 2.5% by weight of the total blendcomposition of a compatibilizing ethylene copolymer having the formulaE/X/Y where E is ethylene, X is an α, β-ethylenically unsaturatedmonomer derived from at least one of alkylacrylate, alkylmethacrylate,alkyl vinyl ether, carbon monoxide, sulfur dioxide, or mixtures thereof,where the alkyl groups contain 1-12 carbon atoms, and Y is an α,β-ethylenically unsaturated monomer containing a reactive group thatforms a covalent bond with said first polymeric component.
 2. Thepolymeric blend of claim 1, wherein said first polymeric componentcomprises about 60-77% of the total blend composition, and is selectedfrom the group consisting of polyethylene-terephthalate,polybutylene-terephthalate, glycol modified polyethylene-terephthalate,1,4-cyclohexylene dimethylene terephthalate/isophthalate copolymer,linear homopolymer esters derived from aromatic dicarboxylic acids andglycols of the general formula HO(CH₂)_(n)OH where n is an integer from2 to
 10. 3. The polymeric blend of claim 1, wherein said first polymericcomponent is a polyester with glycol segments selected from the groupconsisting of ethylene glycol; 1,3-trimethylene glycol;1,4-tetramethylene glycol; 1,6-hexamethylene glycol; 1,8-octamethyleneglycol; 1,10-decamethylene glycol; 2,2-dimethyl-1,3-propane diol;1,3-propylene glycol; 1,4-butylene glycol; neopentyl glycol andcyclohexane dimethanol.
 4. The polymeric blend of claim 1, wherein saidsecond polymeric component is a softening ethylene copolymer comprisingabout 23-40% by weight of the total blend composition, and saidsoftening ethylene copolymer contains ethylene and at least one othermonomer selected from the group consisting of α, β-ethylenicallyunsaturated monomers, carbon monoxide, and sulfur dioxide.
 5. Thepolymeric blend of claim 1, wherein said second polymeric component is asoftening ethylene copolymer comprising about 23-40% by weight of thetotal blend composition, and the ethylene copolymer has the formula E′X′or E′X′Y′, where E′ is ethylene, and is about 60-85% by weight of theethylene copolymer, and where X′ is about 15-40% by weight of theethylene copolymer, and X′ is selected from the group consisting ofmethylacrylate, ethylacrylate, propylacrylate, butylacrylate, andmixtures thereof, and Y′ is selected from the group consisting of α,β-ethylenically unsaturated monocarboxylic acids, 60 , β-ethylenicallyunsaturated dicarboxylic acids, and anhydrides comprising about 0.5-15%by weight of the ethylene copolymer.
 6. The polymeric blend of claim 1,wherein said second polymeric component is a softening ethylenecopolymer comprising about 23-40% by weight of the total blendcomposition, and the ethylene copolymer is selected from the groupconsisting of ethylene/methylacrylate/sulfur dioxide,ethylene/butylacrylate/carbon monoxide, ethylene/methylacrylate,ethylene ethylacrylate, ethylene/butylacrylate, ethylene/vinylacetate,ethylene/methacrylic acid, ethylene/butylacrylate/methacrylic acid,ethylene/methylacrylate/methacrylic acid, ethylene/methylacrylate/maleicanhydride, ethylene/ethylacrylate/maleic anhydride, andethylene/butylacrylate/maleic anhydride.
 7. The polymeric blend of claim4, wherein one of the α, β-ethylenically unsaturated monomers is an acidcontaining moiety, the polymer is partially neutralized with an ionselected from the group of sodium, potassium, zinc, lithium, calcium,and ammonium.
 8. The polymeric blend of claim 1, wherein said secondpolymeric component is a polyolefin selected from the group consistingof elastomeric ethylene-propylene copolymers, linear low densitypolyethylene, and linear low density polyethylene including maleicanhydride.
 9. The polymeric blend of claim 1, wherein said secondpolymer component is a polyester block copolymer comprising at least onesegment selected from the group consisting of polyethylene-terephthalateand polybutylene-terephthalate, and at least one segment of a polyether.10. The polymeric blend of claim 9, wherein said polyether is selectedfrom the group consisting of polyethylene glycol, polypropylene glycol,polytetramethylene glycol ethers, polyetherimide esters, andpoly(alkylene oxide) glycols in which the alkylene group has 2-10 carbonatoms.
 11. The polymeric blend of claim 9, wherein said polyether isselected from the group consisting of poly(ethylene oxide) glycol,poly(1,2- and 1,3-propylene oxide) glycol, poly(tetramethylene oxide)glycol, poly(pentamethylene oxide) glycol, poly(hexamethylene oxide)glycol, poly(heptamethylene oxide) glycol, poly(octamethylene oxide)glycol, poly(nonamethylene oxide) glycol, poly(1,2-butylene oxide)glycol, random or block copolymers of ethylene oxide and 1,2-propyleneoxide, and poly-formals prepared by reacting formaldehyde with glycols,glycols formed from dicarboxymethyl acids of poly(alkylene oxides), andmixtures thereof.
 12. The polymeric blend of claim 11, wherein thepolyether is propylene glycol.
 13. The polymeric blend of claim 11,wherein the polyether is a mixture of tetramethylene glycol andpentamethylene glycol.
 14. The polymeric blend of claim 1, wherein X isselected from the group consisting of vinyl acetate, methylacrylate,butylacrylate, and methyl vinyl ether.
 15. The polymeric blend of claim1, wherein Y is an α, β-ethylenically unsaturated monomer containing areactive group selected from the group consisting of epoxide, maleicanhydride, isocyanate, or oxazoline.
 16. The polymeric blend of claim 1,wherein X is a moiety derived from at least one of alkyl acrylate, alkylmethacrylate, alkyl vinyl ether, carbon monoxide, sulfur dioxide, ormixtures thereof.
 17. The polymeric blend of claim 1, wherein Y isselected from the group consisting of glycidyl methacrylate, glycidylacrylate, maleic anhydride, and isocyanato-ethylmethacrylate.
 18. Thepolymeric blend of claim 1, wherein Y is a moiety derived from at leastone alkyl acrylate, alkyl methacrylate, or mixtures thereof, where thealkyl groups contain 1-8 carbon atoms.
 19. The polymeric blend of claim1, wherein Y is selected from the group consisting of glycidyl acrylate,glycidyl methacrylate, and epoxide containing copolymerizable monomers.20. The polymeric blend of claim 15, wherein the α, β-ethylenicallyunsaturated monomer comprises an unsaturated mono-carboxylic acidcontaining an acid moiety, and the acid moiety in the unsaturatedmono-carboxylic acid is neutralized at least partially by at least onemetal ion selected from the group consisting of sodium, zinc, magnesium,calcium, potassium, and lithium.
 21. The polymeric blend of claim 1,wherein E is ethylene, and is 67% by weight of the compatibilizingethylene copolymer; X is selected from the group of methylacrylate,ethylacrylate and butylacrylate, and is about 15-30% by weight of thecompatibilizing ethylene copolymer; and Y is selected from the groupconsisting of glycidyl acrylate and glycidyl methacrylate, and is about8% by weight of the compatibilizing ethylene copolymer.
 22. Thepolymeric blend of claim 1, wherein said polymeric blend is irradiated.23. The polymeric blend of claim 22, wherein said polymeric blend isirradiated using ionizing radiation generated by any of an electronbeam, gamma rays, ultraviolet light, or a molecular beam.
 24. Thepolymeric blend of claim 22, wherein said polymeric blend is irradiatedby an electron beam in the range of about 10-100 Mrads.
 25. Thepolymeric blend of claim 1, wherein said first polymeric component is atleast one polyamide selected from the group consisting of polyamidesproduced by condensation of equimolar amounts of a saturateddicarboxylic acid containing from 4 to 12 carbon atoms with a diamine,in which the diamine contains from 4 to 12 carbon atoms, and copolymersor terpolymers thereof.
 26. The polymeric blend of claim 1, wherein saidfirst polymeric component is at least one polyamide selected from thegroup consisting of nylon 12, nylon 11, nylon 6,12; nylon 6,6; nylon 6;nylon 6,9; nylon 6,10; polyamide block copolymers; polyamides producedby the ring opening of lactams; poly-11-amino-undecanoic acid;bis(paraaminocyclohexyl) methane dodecanoamide; and copolymers orterpolymers thereof.
 27. The polymeric blend of claim 25, wherein saidpolyamide has a melting point in excess of 200° C.
 28. A cathetermaterial formed from polymeric components, comprising: about 10-95% byweight of the total blend composition of a first polymeric componentselected from the group consisting of polyesters and polyamides, saidpolyesters being prepared from the group of dicarboxylic acids selectedfrom aromatic dicarboxylic acids having from 8 to 14 carbon atoms andaliphatic dicarboxylic acids having from 2 to 12 carbon atoms, and atleast one glycol selected from the group consisting of glycols havingthe formula HO(CH₂)_(n)OH, where n is an integer from 2 to 10, neopentylglycol and cyclohexane dimethanol, and said polyamides being branched orstraight chain polyamides having a molecular weight of at least 5000;about 5-90% by weight of the total blend composition of a second polymercomponent having a Shore hardness less than 75 D, selected from thegroup consisting of polyolefins having a density less than 0.93,ethylene copolymers, polyester block copolymers, and polyamide blockcopolymers; and less than about 2.5% by weight of the total blendcomposition of a compatibilizing ethylene copolymer having the formulaE/X/Y where E is ethylene, X is an α, β-ethylenically unsaturatedmonomer derived from at least one of alkylacrylate, alkylmethacrylate,alkyl vinyl ether, carbon monxide, sulfur dioxide, or mixtures thereof,where the alkyl groups contain 1-12 carbon atoms, and Y is an α,β-ethylenically unsaturated monomer containing a reactive group thatforms a covalent bond with said first polymeric component.
 29. Thecatheter material of claim 28, wherein said first polymeric componentcomprises about 60-77% of the total blend composition, and is selectedfrom the group consisting of polyethylene-terephthalate,polybutylene-terephthalate, glycol modified polyethylene-terephthalate,1,4-cyclohexylene dimethylene terephthalate/isophthalate copolymer,linear homopolymer esters derived from aromatic dicarboxylic acids andglycols of the general formula HO(CH₂)_(n)OH where n is an integer from2 to
 10. 30. The catheter material of claim 28, wherein said firstpolymeric component is a polyester having glycol segments selected fromthe group consisting of ethylene glycol; 1,3-trimethylene glycol;1,4-tetramethylene glycol; 1,6-hexamethylene glycol; 1,8-octamethyleneglycol; 1,10-decamethylene glycol; 2,2-dimethyl-1,3-propane diol;1,3-propylene glycol; 1,4-butylene glycol; neopentyl glycol andcyclohexane dimethanol.
 31. The catheter material of claim 28, whereinsaid second polymeric component is a softening ethylene copolymercomprising about 23-40% by weight of the total blend composition, andsaid softening ethylene copolymer contains ethylene and at least oneother monomer selected from the group consisting of α, β-ethylenicallyunsaturated monomers, carbon monoxide, and sulfur dioxide.
 32. Thecatheter material of claim 28, wherein said second polymeric componentis a softening ethylene copolymer comprising about 23-40% by weight ofthe total blend composition, and the ethylene copolymer has the formulaE′X′ or E′X′Y′, where E′ is ethylene, and is about 60-85% by weight ofthe ethylene copolymer, where X′ is about 15-40% by weight of theethylene copolymer, and is selected from the group consisting ofmethylacrylate, ethylacrylate, propylacrylate, butylacrylate andmixtures thereof, and Y′ is selected from the group consisting of α,⊕-ethylenically unsaturated monocarboxylic acids, α, β-ethylenicallyunsaturated dicarboxylic acids, and anhydrides comprising about 0.5-15%by weight of the ethylene copolymer.
 33. The catheter material of claim28, wherein said second polymeric component is a softening ethylenecopolymer comprising about 23-40% by weight of the total blendcomposition, and the ethylene copolymer is selected from the groupconsisting of ethylene/methylacrylate/sulfur dioxide,ethylene/butylacrylate/carbon monoxide, ethylene/methylacrylate,ethylene ethylacrylate, ethylene/butylacrylate, ethylene/vinylacetate,ethylene/methacrylic acid, ethylene/butylacrylate/methacrylic acid,ethylene/methylacrylate/methacrylic acid, ethylene/methylacrylate/maleicanhydride, ethylene/ethylacrylate/maleic anhydride, andethylene/butylacrylate/maleic anhydride.
 34. The catheter material ofclaim 31, wherein one of the α, β-ethylenically unsaturated monomers isan acid containing moiety, the polymer is partially neutralized with anion selected from the group of sodium, potassium, zinc, lithium,calcium, and ammonium.
 35. The catheter material of claim 28, whereinsaid second polymeric component is a polyolefin selected from the groupconsisting of elastomeric ethylene-propylene copolymers, linear lowdensity polyethylene, and linear low density polyethylene includingmaleic anhydride.
 36. The catheter material of claim 28, wherein saidsecond polymer component is a polyester block copolymer comprising atleast one segment selected from the group consisting ofpolyethylene-terephthalate and polybutylene-terephthalate, and at leastone segment of a polyether.
 37. The catheter material of claim 36,wherein said polyether is selected from the group consisting ofpolyethylene glycol, polypropylene glycol, polytetramethylene glycolethers, polyetherimide esters, and poly(alkylene oxide) glycols in whichthe alkylene group has 2-10 carbon atoms.
 38. The catheter material ofclaim 36, wherein said polyether is selected from the group consistingof poly(ethylene oxide) glycol, poly(1,2- and 1,3-propylene oxide)glycol, poly(tetramethylene oxide) glycol, poly(pentamethylene oxide)glycol, poly(hexamethylene oxide) glycol, poly(heptamethylene oxide)glycol, poly(octamethylene oxide) glycol, poly(nonamethylene oxide)glycol, poly(1,2-butylene oxide) glycol, random or block copolymers ofethylene oxide and 1,2-propylene oxide, and poly-formals prepared byreacting formaldehyde with glycols, glycols formed from dicarboxymethylacids of poly(alkylene oxides), and mixtures thereof.
 39. The cathetermaterial of claim 38, wherein the polyether is propylene glycol.
 40. Thecatheter material of claim 38, wherein the polyether is a mixture oftetramethylene glycol and pentamethylene glycol.
 41. The cathetermaterial of claim 28, wherein X is selected from the group consisting ofvinyl acetate, methylacrylate, butylacrylate, and methyl vinyl ether.42. The catheter material of claim 28, wherein Y is an α,β-ethylenically unsaturated monomer containing a reactive group selectedfrom the group consisting of epoxide, maleic anhydride, isocyanate, oroxazoline.
 43. The catheter material of claim 28, wherein X is a moietyderived from at least one of alkyl acrylate, alkyl methacrylate, alkylvinyl ether, carbon monoxide, sulfur dioxide, or mixtures thereof. 44.The catheter material of claim 28, wherein Y is selected from the groupconsisting of glycidyl methacrylate, glycidyl acrylate, maleicanhydride, and isocyanato-ethylmethacrylate.
 45. The catheter materialof claim 28, wherein Y is a moiety derived from at least one alkylacrylate, alkyl methacrylate, or mixtures thereof, where the alkylgroups contain 1-8 carbon atoms.
 46. The catheter material of claim 28,wherein Y is selected from the group consisting of glycidyl acrylate,glycidyl methacrylate, and epoxide containing copolymerizable monomers.47. The catheter material of claim 42, wherein the ≢, β-ethylenicallyunsaturated monomer comprises an unsaturated mono-carboxylic acidcontaining an acid moiety, and the acid moiety in the unsaturatedmono-carboxylic acid is neutralized at least partially by at least onemetal ion selected from the group consisting of sodium, zinc, magnesium,calcium, potassium, and lithium.
 48. The catheter material of claim 28,wherein E is ethylene, and is 67% by weight of the compatibilizingethylene copolymer; X is selected from the group of methylacrylate,ethylacrylate and butylacrylate, and is about 15-30% by weight of thecompatibilizing ethylene copolymer; and Y is selected from the groupconsisting of glycidyl acrylate and glycidyl methacrylate, and is about8% by weight of the compatibilizing ethylene copolymer.
 49. The cathetermaterial of claim 28, wherein said polymeric blend is irradiated. 50.The catheter material of claim 49, wherein said polymeric blend isirradiated using ionizing radiation generated by any of an electronbeam, gamma rays, ultraviolet light, or a molecular beam.
 51. Thecatheter material of claim 49, wherein said polymeric blend isirradiated by an electron beam in the range of about 10-100 Mrads. 52.The catheter material of claim 28, wherein said first polymericcomponent is at least one polyamide selected from the group consistingof polyamides produced by condensation of equimolar amounts of asaturated dicarboxylic acid containing from 4 to 12 carbon atoms with adiamine, in which the diamine contains from 4 to 12 carbon atoms, andcopolymers or terpolymers thereof.
 53. The catheter material of claim28, wherein said first polymeric component is at least one polyamideselected from the group consisting of nylon 12, nylon 11, nylon 6,12;nylon 6,6; nylon 6; nylon 6,9; nylon 6,10; polyamide block copolymers;polyamides produced by the ring opening of lactams;poly-11-amino-undecanoic acid; bis(paraaminocyclohexyl) methanedodecanoamide; and copolymers or terpolymers thereof.
 54. The cathetermaterial of claim 52, wherein said polyamide has a melting point inexcess of 200° C.
 55. A balloon material formed from a blend compositionof polymeric components, comprising: about 10-95% by weight of the totalblend composition of a first polymeric component selected from the groupconsisting of polyesters and polyamides, said polyesters being preparedfrom the group of dicarboxylic acids selected from aromatic dicarboxylicacids having from 8 to 14 carbon atoms and aliphatic dicarboxylic acidshaving from 2 to 12 carbon atoms, and at least one glycol selected fromthe group consisting of glycols having the formula HO(CH₂)_(n)OH, wheren is an integer from 2 to 10, neopentyl glycol and cyclohexanedimethanol, and said polyamides being branched or straight chainpolyamides having a molecular weight of at least 5000; about 5-90% byweight of the total blend composition of a second polymer componenthaving a Shore hardness less than 75 D, selected from the groupconsisting of polyolefins having a density less than 0.93, ethylenecopolymers, polyester block copolymers, and polyamide block copolymers;and less than about 2.5% by weight of the total blend composition of acompatibilizing ethylene copolymer having the formula E/X/Y where E isethylene, X is an α, β-ethylenically unsaturated monomer derived from atleast one of alkylacrylate, alkylmethacrylate, alkyl vinyl ether, carbonmonxide, sulfur dioxide, or mixtures thereof, where the alkyl groupscontain 1-12 carbon atoms, and Y is an ≢, β-ethylenically unsaturatedmonomer containing a reactive group that forms a covalent bond with saidfirst polymeric component.
 56. The balloon material of claim 55, whereinsaid first polymeric component comprises about 60-77% of the total blendcomposition, and is selected from the group consisting ofpolyethylene-terephthalate, polybutylene-terephthalate, glycol modifiedpolyethylene-terephthalate, 1,4-cyclohexylene dimethyleneterephthalate/isophthalate copolymer, linear homopolymer esters derivedfrom aromatic dicarboxylic acids and glycols of the general formulaHO(CH₂)_(n)OH where n is an integer from 2 to
 10. 57. The balloonmaterial of claim 55, wherein said first polymeric component is a glycolselected from the group consisting of ethylene glycol; 1,3-trimethyleneglycol; 1,4-tetramethylene glycol; 1,6-hexamethylene glycol;1,8-octamethylene glycol; 1,10-decamethylene glycol;2,2-dimethyl-1,3-propane diol; 1,3-propylene glycol; 1,4-butyleneglycol; neopentyl glycol and cyclohexane dimethanol.
 58. The balloonmaterial of claim 55, wherein said second polymeric component is asoftening ethylene copolymer comprising about 23-40% by weight of thetotal blend composition, and said softening ethylene copolymer containsethylene and at least one other monomer selected from the groupconsisting of α, β-ethylenically unsaturated monomers, carbon monoxide,and sulfur dioxide.
 59. The balloon material of claim 55, wherein saidsecond polymeric component is a softening ethylene copolymer comprisingabout 23-40% by weight of the total blend composition, and the ethylenecopolymer has the formula E′X′ or E′X′Y′, where E′ is ethylene, and isabout 60-85% by weight of the ethylene copolymer, where X′ is about15-40% by weight of the ethylene copolymer, and is selected from thegroup consisting of methylacrylate, ethylacrylate, propylacrylate,butylacrylate and mixtures thereof, and Y′ is selected from the groupconsisting of α, β-ethylenically unsaturated monocarboxylic acids, α,β-ethylenically unsaturated dicarboxylic acids, and anhydridescomprising about 0.5-15% by weight of the ethylene copolymer.
 60. Theballoon material of claim 55, wherein said second polymeric component isa softening ethylene copolymer comprising about 23-40% by weight of thetotal blend composition, and the ethylene copolymer is selected from thegroup consisting of ethylene/methylacrylate/sulfur dioxide,ethylene/butylacrylate/carbon monoxide, ethylene/methylacrylate,ethylene ethylacrylate, ethylene/butylacrylate, ethylene/vinylacetate,ethylene/methacrylic acid, ethylene/butylacrylate/methacrylic acid,ethylene/methylacrylate/methacrylic acid, ethylene/methylacrylate/maleicanhydride, ethylene/ethylacrylate/maleic anhydride, andethylene/butylacrylate/maleic anhydride.
 61. The balloon material ofclaim 58, wherein one of the α, β-ethylenically unsaturated monomers isan acid containing moiety, the polymer is partially neutralized with anion selected from the group of sodium, potassium, zinc, lithium,calcium, and ammonium.
 62. The balloon material of claim 55, whereinsaid second polymeric component is a polyolefin selected from the groupconsisting of elastomeric ethylene-propylene copolymers, linear lowdensity polyethylene, and linear low density polyethylene includingmaleic anhydride.
 63. The balloon material of claim 55, wherein saidsecond polymer component is a polyester block copolymer comprising atleast one segment selected from the group consisting ofpolyethylene-terephthalate and polybutylene-terephthalate, and at leastone segment of a polyether.
 64. The balloon material of claim 63,wherein said polyether is selected from the group consisting ofpolyethylene glycol, polypropylene glycol, polytetramethylene glycolethers, polyetherimide esters, and poly(alkylene oxide) glycols in whichthe alkylene group has 2-10 carbon atoms.
 65. The balloon material ofclaim 63, wherein said polyether is selected from the group consistingof poly(ethylene oxide) glycol, poly(1,2- and 1,3-propylene oxide)glycol, poly(tetramethylene oxide) glycol, poly(pentamethylene oxide)glycol, poly(hexamethylene oxide) glycol, poly(heptamethylene oxide)glycol, poly(octamethylene oxide) glycol, poly(nonamethylene oxide)glycol, poly(1,2-butylene oxide) glycol, random or block copolymers ofethylene oxide and 1,2-propylene oxide, and poly-formals prepared byreacting formaldehyde with glycols, glycols formed from dicarboxymethylacids of poly(alkylene oxides), and mixtures thereof.
 66. The balloonmaterial of claim 65, wherein the polyether is propylene glycol.
 67. Theballoon material of claim 65, wherein the polyether is a mixture oftetramethylene glycol and pentamethylene glycol.
 68. The balloonmaterial of claim 55, wherein X is selected from the group consisting ofvinyl acetate, methylacrylate, butylacrylate, and methyl vinyl ether.69. The balloon material of claim 55, wherein Y is an ≢, β-ethylenicallyunsaturated monomer containing a reactive group selected from the groupconsisting of epoxide, maleic anhydride, isocyanate, or oxazoline. 70.The balloon material of claim 55, wherein X is a moiety derived from atleast one of alkyl acrylate, alkyl methacrylate, alkyl vinyl ether,carbon monoxide, sulfur dioxide, or mixtures thereof.
 71. The balloonmaterial of claim 55, wherein Y is selected from the group consisting ofglycidyl methacrylate, glycidyl acrylate, maleic anhydride, andisocyanato-ethylmethacrylate.
 72. The balloon material of claim 55,wherein Y is a moiety derived from at least one alkyl acrylate, alkylmethacrylate, or mixtures thereof, where the alkyl groups contain 1-8carbon atoms.
 73. The balloon material of claim 55, wherein Y isselected from the group consisting of glycidyl acrylate, glycidylmethacrylate, and epoxide containing copolymerizable monomers.
 74. Theballoon material of claim 69, wherein the α, β-ethylenically unsaturatedmonomer comprises an unsaturated mono-carboxylic acid containing an acidmoiety, and the acid moiety in the unsaturated mono-carboxylic acid isneutralized at least partially by at least one metal ion selected fromthe group consisting of sodium, zinc, magnesium, calcium, potassium, andlithium.
 75. The balloon material of claim 55, wherein E is ethylene,and is 67% by weight of the compatibilizing ethylene copolymer; X isselected from the group of methylacrylate, ethylacrylate andbutylacrylate, and is about 15-30% by weight of the compatibilizingethylene copolymer; and Y is selected from the group consisting ofglycidyl acrylate and glycidyl methacrylate, and is about 8% by weightof the compatibilizing ethylene copolymer.
 76. The balloon material ofclaim 55, wherein said polymeric blend is irradiated.
 77. The balloonmaterial of claim 76, wherein said polymeric blend is irradiated usingionizing radiation generated by any of an electron beam, gamma rays,ultraviolet light, or a molecular beam.
 78. The balloon material ofclaim 76, wherein said polymeric blend is irradiated by an electron beamin the range of about 10-100 Mrads.
 79. The balloon material of claim55, wherein said first polymeric component is at least one polyamideselected from the group consisting of polyamides produced bycondensation of equimolar amounts of a saturated dicarboxylic acidcontaining from 4 to 12 carbon atoms with a diamine, in which thediamine contains from 4 to 12 carbon atoms, and copolymers orterpolymers thereof.
 80. The balloon material of claim 55, wherein saidfirst polymeric component is at least one polyamide selected from thegroup consisting of nylon 12, nylon 11, nylon 6,12; nylon 6,6; nylon 6;nylon 6,9; nylon 6,10; polyamide block copolymers; polyamides producedby the ring opening of lactams; poly-11-amino-undecanoic acid;bis(paraaminocyclohexyl) methane dodecanoamide; and copolymers orterpolymers thereof.
 81. The balloon material of claim 79, wherein saidpolyamide has a melting point in excess of 200° C.
 82. A dilatationcatheter balloon material formed from a blend composition of polymericcomponents, comprising: about 60-77% by weight of the total blendcomposition of a first polymeric component selected from the groupconsisting of polyethylene-terephthalate, polybutylene-terephthalate,glycol modified polyethylene-terephthalate, 1,4-cyclohexylenedimethylene terephthalate/isophthalate copolymer, linear homopolymeresters derived from aromatic dicarboxylic acids and glycols of thegeneral formula HO(CH₂)_(n)OH where n is an integer from 2 to 10; about23-40% by weight of the total blend composition of a second polymericcomponent comprising an ethylene copolymer containing ethylene and atleast one other monomer selected from the group consisting of α,β-ethylenically unsaturated monomers, carbon monoxide, and sulfurdioxide; and from about 0.25% to about 2.5% by weight of the total blendcomposition of a compatibilizing ethylene copolymer having the formulaE/X/Y where E is ethylene, X is an α, β-ethylenically unsaturatedmonomer derived from at least one of alkylacrylate, alkylmethacrylate,alkyl vinyl ether, carbon monoxide, sulfur dioxide, or mixtures thereof,where the alkyl groups contain 1-12 carbon atoms, and Y is an α,β-ethylenically unsaturated monomer containing a reactive group thatforms a covalent bond with said first polymeric component.
 83. Thedilatation catheter balloon material of claim 82, wherein said secondpolymeric component is an ethylene copolymer having the formula E′X′orE′X′Y′, where E′is ethylene, and is about 60-85% by weight of theethylene copolymer, where X′ is about 15-40% by weight of the ethylenecopolymer, and is selected from the group consisting of alkylacrylate,where the alkyl group contains 1-4 carbon atoms, and mixtures thereof,and Y′ is selected from the group consisting of α, β-ethylenicallyunsaturated monocarboxylic acids, α, β-ethylenically unsaturateddicarboxylic acids, and anhydrides comprising about 0.5-15% by weight ofthe ethylene copolymer.
 84. The dilatation catheter balloon material ofclaim 82, wherein one of the ≢, β-ethylenically unsaturated monomers ofthe second polymeric component is an acid containing moiety, and thepolymer is partially neutralized with an ion selected from the group ofsodium, potassium, zinc, lithium, calcium, and ammonium.
 85. Thedilatation catheter balloon material of claim 82, wherein Y is selectedfrom the group consisting of glycidyl methacrylate, glycidyl acrylate,maleic anhydride, and isocyanato-ethylmethacrylate.
 86. The dilatationcatheter balloon material of claim 82, wherein E is ethylene, and is 67%by weight of the compatibilizing ethylene copolymer; X is selected fromthe group of methylacrylate, ethylacrylate and butylacrylate, and isabout 15-30% by weight of the compatibilizing ethylene copolymer; and Yis selected from the group consisting of glycidyl acrylate and glycidylmethacrylate, and is about 8% by weight of the compatibilizing ethylenecopolymer.
 87. A radiation cross-linked polymeric blend, comprising:about 10-95% by weight of the total blend composition of a firstpolymeric component selected from the group consisting of polyesters,said polyesters being prepared from the group of dicarboxylic acidsselected from aromatic dicarboxylic acids having from 8 to 14 carbonatoms and aliphatic dicarboxylic acids having from 2 to 12 carbon atoms,and at least one glycol selected from the group consisting of glycolshaving the formula HO(CH₂)_(n)OH, where n is an integer from 2 to 10,neopentyl glycol and cyclohexane dimethanol; about 5-90% by weight ofthe total blend composition of a second polymer component having a Shorehardness less than 75 D, selected from the group consisting ofpolyolefins having a density less than 0.93, ethylene copolymers, andpolyester block copolymers; and less than about 2.5% by weight of thetotal blend composition of a compatibilizing ethylene copolymer havingthe formula E/X/Y where E is ethylene, X is an α, β-ethylenicallyunsaturated monomer derived from at least one of alkylacrylate,alkylmethacrylate, alkyl vinyl ether, carbon monoxide, sulfur dioxide,or mixtures thereof, where the alkyl groups contain 1-12 carbon atoms,and Y is an α, β-ethylenically unsaturated monomer containing a reactivegroup that forms a covalent bond with said first polymeric component.88. A catheter material formed from a radiation cross-linked polymericblend, comprising: about 10-95% by weight of the total blend compositionof a first polymeric component selected from the group consisting ofpolyesters, said polyesters being prepared from the group ofdicarboxylic acids selected from aromatic dicarboxylic acids having from8 to 14 carbon atoms and aliphatic dicarboxylic acids having from 2 to12 carbon atoms, and at least one glycol selected from the groupconsisting of glycols having the formula HO(CH₂)_(n)OH, where n is aninteger from 2 to 10, neopentyl glycol and cyclohexane dimethanol; about5-90% by weight of the total blend composition of a second polymercomponent having a Shore hardness less than 75 D, selected from thegroup consisting of polyolefins having a density less than 0.93,ethylene copolymers, and polyester block copolymers; and less than about2.5% by weight of the total blend composition of a compatibilizingethylene copolymer having the formula E/X/Y where E is ethylene, X is anα, β-ethylenically unsaturated monomer derived from at least one ofalkylacrylate, alkylmethacrylate, alkyl vinyl ether, carbon monoxide,sulfur dioxide, or mixtures thereof, where the alkyl groups contain 1-12carbon atoms, and Y is an α, β-ethylenically unsaturated monomercontaining a reactive group that forms a covalent bond with said firstpolymeric component.
 89. A balloon material formed from a radiationcross-linked polymeric blend, comprising: about 10-95% by weight of thetotal blend composition of a first polymeric component selected from thegroup consisting of polyesters, said polyesters being prepared from thegroup of dicarboxylic acids selected from aromatic dicarboxylic acidshaving from 8 to 14 carbon atoms and aliphatic dicarboxylic acids havingfrom 2 to 12 carbon atoms, and at least one glycol selected from thegroup consisting of glycols having the formula HO(CH₂)_(n)OH, where n isan integer from 2 to 10, neopentyl glycol and cyclohexane dimethanol;about 5-90% by weight of the total blend composition of a second polymercomponent having a Shore hardness less than 75 D, selected from thegroup consisting of polyolefins having a density less than 0.93,ethylene copolymers, and polyester block copolymers; and less than about2.5% by weight of the total blend composition of a compatibilizingethylene copolymer having the formula E/X/Y where E is ethylene, X is an≢, β-ethylenically unsaturated monomer derived from at least one ofalkylacrylate, alkylmethacrylate, alkyl vinyl ether, carbon monoxide,sulfur dioxide, or mixtures thereof, where the alkyl groups contain 1-12carbon atoms, and Y is an α, β-ethylenically unsaturated monomercontaining a reactive group that forms a covalent bond with said firstpolymeric component.
 90. A polymeric blend, comprising: about 10-95% byweight of the total blend composition of a first polymeric componentselected from the group consisting of polyesters and polyamides, saidpolyesters being prepared from the group of dicarboxylic acids selectedfrom aromatic dicarboxylic acids having from 8 to 14 carbon atoms andaliphatic dicarboxylic acids having from 2 to 12 carbon atoms, and atleast one glycol selected from the group consisting of glycols havingthe formula HO(CH₂)_(n)OH, where n is an integer from 2 to 10, neopentylglycol and cyclohexane dimethanol, and said polyamides being branched orstraight chain polyamides having a molecular weight of at least 5000;and about 5-90% by weight of the total blend composition of a secondpolymer component having a Shore hardness less than 75 D, selected fromthe group consisting of polyolefins having a density less than 0.93,ethylene copolymers, polyester block copolymers, and polyamide blockcopolymers.
 91. The polymeric blend of claim 90, wherein said polymericblend is irradiated.
 92. A catheter material formed from a blend ofpolymeric components, comprising: about 10-95% by weight of the totalblend of a first polymeric component selected from the group consistingof polyesters and polyamides, said polyesters being prepared from thegroup of dicarboxylic acids selected from aromatic dicarboxylic acidshaving from 8 to 14 carbon atoms and aliphatic dicarboxylic acids havingfrom 2 to 12 carbon atoms, and at least one glycol selected from thegroup consisting of glycols having the formula HO(CH₂)_(n)OH, where n isan integer from 2 to 10, neopentyl glycol and cyclohexane dimethanol,and said polyamides being branched or straight chain polyamides having amolecular weight of at least 5000; and about 5-90% by weight of thetotal blend composition of a second polymer component having a Shorehardness less than 75 D, selected from the group consisting ofpolyolefins having a density less than 0.93, ethylene copolymers,polyester block copolymers, and polyamide block copolymers.
 93. Thepolymeric blend of claim 92, wherein said catheter material isirradiated.
 94. A balloon material formed from a blend of polymericcomponents, comprising: about 10-95% by weight of the total blend of afirst polymeric component selected from the group consisting ofpolyesters and polyamides, said polyesters being prepared from the groupof dicarboxylic acids selected from aromatic dicarboxylic acids havingfrom 8 to 14 carbon atoms and aliphatic dicarboxylic acids having from 2to 12 carbon atoms, and at least one glycol selected from the groupconsisting of glycols having the formula HO(CH₂)_(n)OH, where n is aninteger from 2 to 10, neopentyl glycol and cyclohexane dimethanol, andsaid polyamides being branched or straight chain polyamides having amolecular weight of at least 5000; and about 5-90% by weight of thetotal blend composition of a second polymer component having a Shorehardness less than 75 D, selected from the group consisting ofpolyolefins having a density less than 0.93, ethylene copolymers,polyester block copolymers, and polyamide block copolymers.
 95. Thepolymeric blend of claim 94, wherein said balloon material isirradiated.